Today, in developed societies, people suffering with obesity are rapidly increasing because of enriched eating habits. People with high obesity indexes are two or three times more liable to diabetes, atherosclerosis, and heart diseases than those with normal weights. Diseases deeply related to obesity such as gout, complications after surgery, cholelithiasis, lumbago, and hepatic diseases are also increasing steadily. Obesity is thus becoming a serious problem from the viewpoint of health care.
Under such conditions, reduction of food intake is thought of as an effective method of preventing and curing obesity. Since reducing the amount of food, however, is very hard to continue because of a strong feeling of hunger, the following methods are usually used simultaneously.
One of them is to reduce the capacity of the stomach of patients by putting a balloon in the stomach or blocking a major part of the stomach so that a small amount of food can invoke a mechanical stretching stimulus to the stomach. However, this method is not desirable because it requires surgery, and in addition there is fear of possible side effects.
The other method is to have patients consume bulking agents such as dietary fiber substances of high viscosity, optionally mixed with other foods. This method is intended to reduce the available energy content per unit weight of foods, taking advantage of the undigestibility of such bulking agents. However, this method is not desirable because it requires intake of a large amount of such bulking agents which are not essential nutrients or cause diarrhea or constipation.
Recently, it has been suggested that foods containing carbohydrates which are slowly digestively absorbed are useful to prevent obesity, even though their avilable energy content are not reduced (Jenkins, D. J. A., et al., Am. J. Clin. Nutr. 34: MARCH 1981, pp. 362-366). This method indicates that post-prandial blood glucose and insulin secretion are reduced by the intake of such carbohydrates, and also indicates that high-amylose cornstarch (amylomaze starch) is useful as the source of such carbohydrates. However, amylomaze starch cannot be used for the main source of daily starchy foods with an effective amount, as its taste and texture are not good enough.
The present invention, therefore, provides methods preparing a modified wheat flour which is digestively absorbed slowly, has the same taste and texture as a natural flour, and is useful for the source of daily starchy foods, by the modification of the flour under the presence of fatty acid compounds without gelatinization.
Further, a method is disclosed in Japanese patent application publication gazette No. 13177/1984. The object of this method is not to slow the digestion or absorption, but to improve the drawability of bread dough and prevents its aging.
Binding of starch and a fatty acid ester are also known, but are suggested for heat-reversible binding between a fatty acid ester and amylose gelatinized by heating, which produce modified starches of bad texture and of completely different characters than natural starches.
Moreover, modified flours for use as a material of various starchy foods are desired to be dried for easiness of processing. However, it takes a long time to dry flours with a high water content without causing gelatinization of the starch in the flours, as starch can readily gelatinize by heating during the drying process.